This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
3GPP third generation partnership project
BS base station
CQI channel quality indicator
CSI channel state information
CSI-RS channel state information reference signal
DL downlink (eNB towards UE)
eNB E-UTRAN Node B (evolved Node B)
EPC evolved packet core
E-UTRAN evolved UTRAN (LTE)
FDMA frequency division multiple access
HSPA high speed packet access
IMTA international mobile telecommunications association
ITU-R international telecommunication union-radiocommunication sector
LPN low power node
LTE long term evolution of UTRAN (E-UTRAN)
LTE-A LTE advanced
MAC medium access control (layer 2, L2)
MIMO multiple input multiple output
MM/MME mobility management/mobility management entity
NodeB base station
OFDMA orthogonal frequency division multiple access
O&M operations and maintenance
PDCP packet data convergence protocol
PHY physical (layer 1, L1)
PMI precoding matrix indicator
PDSCH physical downlink shared channel
PUCCH physical uplink control channel
PUSCH physical uplink shared channel
Rel release
RI rank indicator
RLC radio link control
RRC radio resource control
RRH remote radio head
RRM radio resource management
RS reference signal
RSRP reference signal received power
RSRQ reference signal received quality
SGW serving gateway
SINR signal to interference plus noise ratio
SRS sounding reference signal
SC-I-DMA single carrier, frequency division multiple access
UE user equipment, such as a mobile station, mobile node or mobile terminal
UL uplink (UE towards eNB)
UPE user plane entity
UTRAN universal terrestrial radio access network
One modern communication system is known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE or as E-UTRA). In this system the DL access technique is OFDMA, and the UL access technique is SC-FDMA.
One specification of interest is 3GPP TS 36.300 V10.5.0 (2011-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 10) incorporated by reference herein in its entirety and referred to for simplicity hereafter as 3GPP TS 36.300.
FIG. 1A reproduces a diagram from 3GPP TS 36.300 and shows the overall architecture of the E-UTRAN system (Rel-8). The E-UTRAN system includes eNBs, providing the E-UTRAN user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UEs. The eNBs are interconnected with each other by means of an X2 interface. The eNBs are also connected by means of an S1 interface to an EPC, more specifically to a MME by means of a S1 MME interface and to a S-GW by means of a S1 interface (MME/S-GW 4). The S1 interface supports a many-to-many relationship between MMEs/S-GWs/UPEs and eNBs.
The eNB hosts the following functions:
functions for RRM: RRC, Radio Admission Control, Connection Mobility Control, Dynamic allocation of resources to UEs in both UL and DL (scheduling);
IP header compression and encryption of the user data stream;
selection of a MME at UE attachment;
routing of User Plane data towards the EPC (MME/S-GW);
scheduling and transmission of paging messages (originated from the MME);
scheduling and transmission of broadcast information (originated from the MME or O&M); and
a measurement and measurement reporting configuration for mobility and scheduling.
Of particular interest herein are further releases of 3GPP LTE (e.g., LIE Rel-10) targeted towards future IMT-A systems, referred to herein for convenience simply as LTE-Advanced (LTE-A).
Reference in this regard may be made to 3GPP TR 36.913 V10.0.0 (2011-03) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Requirements for further advancements for Evolved Universal Terrestrial Radio Access (E-UTRA) (LIE-Advanced)(Release 10). Reference can also be made to 3GPP TR 36.912 V10.0.0 (2011-03) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Feasibility study for Further Advancements for E-UTRA (LTE-Advanced) (Release 10).
A goal of LTE-A is to provide significantly enhanced services by means of higher data rates and lower latency with reduced cost. LIE-A is directed toward extending and optimizing the 3GPP LTE Rel-8 radio access technologies to provide higher data rates at lower cost. LTE-A will be a more optimized radio system fulfilling the ITU-R requirements for IMT-Advanced while keeping the backward compatibility with LTE Rel-8.
Uplink and downlink frames (of 10 msec duration) are defined in 3GPP TS 36.211 V 10.3.0 (2011-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 10). FIG. 1B reproduces a diagram from 3GPP: Downlink resource grid, of 3GPP TS 36.211 and shows the relationship of OFDM symbols, subcarriers, resource blocks and resource elements.
Coordinated Multipoint (CoMP) transmission and reception is one of the investigated technologies in 3GPP LTE-A to enhance specifically cell-edge data rates in order to create a more uniform data rate experience for the end-user over the entire cell area. The CoMP techniques involve increased collaboration between different BS nodes in DL transmission to the UE and UL reception from the UE.
Reference in this regard can be made to 3GPP TR 36.819 V11.0.0 (2011-09) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Coordinated multi-point operation for LTE physical layer aspects (Release 11).
Reference can also be made to 3GPP RP-111365, 3GPP Work Item Description: Coordinated Multi-Point Operation for LTE, September 2011.
One scenario relates to a CoMP solution focusing on a heterogeneous network involving the collaboration/cooperation between a macro eNB with high transmission power and lower power eNBs within the macro-eNB coverage area. Specifically, one target scenario assumes a technique using the same cell-ID for all the eNBs/network nodes within the macro-eNB coverage area, which can be referred to as “Intra-cell CoMP”. Reference in this regard can be made to R1-110603, CoMP simulation assumptions, January 2011.